1) As i connected the switch to the battery the green light on. But with the magnet i can not turn off the switch. What i’m doing wrong?

On page 2 of the manual, you can see a picture of the switch, which illustrate the battery side and receiving side. If this sides are swapped. The switch will look like it is always on. The switch will not be damaged by these sides being replaced.

2) Will the switch hold up to the vibration of a glow model if mounted correctly?

Since there are no moving parts i the switch, it can withstand strong vibration. Keep the switch in place, on the inside of the fuselage, with silicon or a piece of foam. And it can easily withstand the vibrations from an combustion engine.

3) At what stage will the switch starts (On or Off) after a long period without connecting to a battery?

If the switch has been powered off for more then 10 sec. It’s starts up randomly, when it is powered on.